In a projector that projects an image on a screen (i.e., a projection surface), an optical scanning device is used for scanning a screen with light (for example, laser light) in a horizontal direction and a vertical direction.
In recent years, an optical scanning device has been developed, in which a scanning mirror and a beam structure are integrally formed using MEMS (Micro Electro Mechanical System) technology.
For example, an optical scanning device disclosed in Patent Document 1 includes a beam structure that supports a scanning mirror so that the scanning mirror is rotatable about beams in two directions perpendicular to each other. By rotating the scanning mirror about the beams in the two directions, the screen is scanned with light in a horizontal direction and a vertical direction.
Further, in the optical scanning device disclosed in Patent Document 1, light is emitted to a back side of the beam structure, and an angle of the scanning mirror is detected by detecting reflected light.